Reactive Turning During Walking Improves in Healthy Older Adults with a Novel Task-switching Step Exercise

Reactive Turning During Walking Improves in Healthy Older Adults with a Novel Task-switching Step Exercise | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Reactive Turning During Walking Improves in Healthy Older Adults with a Novel Task-switching Step Exercise Takahito Nakamura, Takahiro Higuchi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6333759/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose : Older adults often experience difficulty maintaining balance during reactive turning while walking, which can occur suddenly and unpredictably. These challenges become more pronounced when the turning direction suddenly switches from the pre-planned side to the opposite side, a phenomenon known as task-switching. This study examined whether Task-Switching Step Exercise (TSSE) designed to enhance reactive turning without requiring turning and even walking—could improve reactive turning performance under a task-switching paradigm in healthy older adults. Methods : Sixty healthy older adults (69.9 ± 4.0 years) were randomly assigned to three groups. The TSSE group prepared a step with the foot indicated by an illuminated arrow and switched feet when the arrow direction changed alongside an auditory cue. The Single-Task Step Exercise group performed pre-planned steps as quickly as possible without task-switching. The Task-Switching Control Exercise group pushed a button while seated, following the task-switching paradigm. All participants completed a single 20-minute exercise session. Pre- and post-tests involved 90-degree reactive turning while walking under the task-switching paradigm. Results : The TSSE group demonstrated significant improvement in center of mass (COM) control, with a reduction in COM acceleration peak from pre- to post-test (p = 0.025). Correlation analyses suggested that some TSSE participants executed COM movement more smoothly and safely during the post-test ( r = -0.56, p = 0.01). Conclusion : Although the effect of TSSE was modest, the exercise may still contribute to improved reactive turning performance in healthy older adults by supporting COM control, even without walking or turning practice. reactive turning task-switching paradigm center of mass step exercise Figures Figure 1 Figure 2 Key summary points Aim : To investigate whether a novel task-switching step exercise (TSSE)—designed to enhance reactive turning without requiring actual turning or walking—could improve reactive turning performance under a task-switching paradigm in healthy older adults. Fundings : Participants who completed TSSE demonstrated improved control of center of mass (COM) movement during reactive turning. Moreover, some participants in the TSSE group exhibited smoother and safer COM movement during reactive turning after exercise. Message : TSSE has the potential to enhance reactive turning performance in healthy older adults, even without walking or turning practice. 1. Introduction Turning while walking increases the risk of falls and related injuries in older adults [ 1 ]. Falls during turns are eight times more likely to result in hip fractures than those occurring during straight-walking [ 2 ]. This heightened risk stems from the dynamic shift of the center of mass (COM) caused by asymmetric coordination of the inner and outer limbs [ 3 ] and the spatiotemporal rotation of the body [ 4 ] in response to the external environment. Specifically, “reactive turning”—a sudden turn initiated at an unpredictable moment [ 5 – 8 ] that requires a response within a limited time—poses challenges to maintaining balance in older adults. The challenges to maintaining balance during reactive turning become more pronounced when the direction of turning is suddenly changed from the pre-planned side to the opposite side, a phenomenon referred to as task-switching [ 7 ]. The task-switching paradigm is commonly used in psychological research [ 9 ]. Under this paradigm, participants of a certain task need to cancel their pre-planned or ongoing action and flexibly adapt to a new one, which induces a performance cost and contributes to reduced performance in older adults. We applied this paradigm to the reactive turning task [ 7 ], in which the direction of travel suddenly switched from the present direction (e.g., right) to the opposite direction (e.g., left) during walking. We tested healthy older adults and found that those with a delayed COM shift to the new direction exhibited larger pelvic rotations over a short period during reactive turning. This suggests that even healthy older adults had difficulty quickly responding and sufficiently rotating their bodies in the new direction when task-switching was required. Therefore, we believe that reactive turning under the task-switching paradigm has the potential to detect performance decline in healthy older adults, and it is essential to consider how to minimize the difficulties they face in this situation. The purpose of the present study was to design a new exercise incorporating the task-switching paradigm to improve reactive turning performance in healthy older adults. We consider that the ability to respond effectively to reactive turning under the task-switching paradigm is a key factor for healthy older adults in discovering potential fall risks and enhancing their performance. However, repetitive turning exercises can be burdensome for individuals facing challenges with reactive turning and may pose the risk of falling during practice. To address these concerns, a novel exercise that targets reactive turning under the task-switching paradigm with an emphasis on safety is needed. Various effective exercises, such as repeated step exercises requiring the selection of an appropriate foot contact location from multiple positions, have been reported to effectively enhance improve responsiveness and balance ability in older adults [ 10 – 12 ]. In Schoene et al. [ 10 ], a choice stepping training program required participants to step onto randomly displayed foot-ground positions. Their findings show improvements after the training in choice stepping reaction time, postural sway, dual-task ability, as assessed by a locomotor balance test, the Timed Up and Go test [ 13 ], while simultaneously performing a verbal fluency task (naming animals). Similarly, Shigematsu and Okura [ 11 ] and Shigematsu et al. [ 12 ] have developed a square-stepping exercise program that includes forward, backward, lateral, and oblique steps with progressively more complex patterns. The findings of Shigematsu et al. [ 12 ] reveal improvements not only in balance ability—such as forward and backward tandem walking and walking around two cones—but also in response time, including weight transfer time while stepping in the forward, backward, right, or left direction after a light signal (choice reaction time), in older adults following the exercise. These findings suggest that repeated-step exercises incorporating cognitive components are effective in improving responsiveness and balance management in older adults. Considering the results of these previous studies, we designed a novel step exercise focused on a task-switching paradigm, called a task-switching step exercise (TSSE). In this exercise, participants prepared to step with the foot indicated by an illuminated arrow direction (left or right) and switched feet when the arrow changed to the opposite direction alongside an auditory cue. Notably, TSSE does not involve turning and even walking. We examined whether, despite these characteristics, TSSE is beneficial to improve reactive turning performance under the task-switching paradigm. In addition to the TSSE group, we established two control exercise groups. The Single-Task Step Exercise (STSE) group served as a control for the TSSE group to assess the effect of the task-switching paradigm. Participants in this group stepped quickly in response to a cue without task-switching. The Task-Switching Control Exercise (TSCE) group served as a control for the TSSE group to isolate the effects of COM movement and stepping. Participants in this group performed task-switching without COM movement by pressing a button with their hands while seated. We first hypothesized that TSSE would enhance older adults’ ability to initiate COM shift and regulate COM acceleration, resulting in improved reactivity and smoother, more stable performance during reactive turning compared to STSE and TSCE. Second, we hypothesized that older adults who initiated COM shift more quickly or demonstrated better COM acceleration control after TSSE would show greater post-test stability. To examine this, we analyzed within-group correlations between pre-and post-test changes in reactive turning performance. 2. Material and Methods 2.1 Participants Sixty healthy older adults (69.9 ± 4.0 years) participated in this study. All participants had normal or corrected-to-normal vision and hearing and no need for a hearing aid. Eligible participants were over 65 years of age and had a Mini-Mental State Examination (MMSE) [14] score of greater than 24. Individuals diagnosed with neurological, orthopedic, or rheumatological diseases that could interfere with locomotion were excluded. This study employed a three-group, single-blind, randomized controlled trial design. The participants were recruited through the Silver Human Resources Center in Koshigaya, Japan. The staff at the center, who were not co-authors of this study, determined the order for each participant. The sample size calculation was performed using G*Power 3.1.9.7 [15]. Assuming a two-way analysis of variance with three groups, an effect size of 0.25, a significant level of 5 %, and a power of 80 %, the required sample size was calculated to be 42 participants. This study was approved by the Ethics Committee of Saitama Prefectural University (No. 22091). All participants provided written informed consent, and the experiment adhered to the principles of the Declaration of Helsinki 2.2 Apparatus The apparatus used for the reactive turning task was almost the same as that used in Nakamura et al. [7] (see Figure 1). The walkway measured 10 meters in length and five meters in width. At a point 6.3 meters from the starting line, an intersection measuring 70 cm by 120 cm was marked by four plastic pylons, each 90 cm in height. A visual cue system comprising a direction indicator (Applied Office, Edogawa, Japan) with illuminated arrows was installed at eye level at the walkway’s end. The direction arrows were illuminated before participants began walking. A pair of infrared sensors were placed at a distance corresponding to two-step lengths from each participant before the edge of the intersection. The same direction indicator system was used during the exercise session. Participants either stood or sat at the intersection edge, approximately four meters from the visual cue. For the TSCE group, two buttons (50 mm × 50 mm), one for each hand, were used, and the cue was adjusted to sitting eye level. Whole-body kinematics were recorded using a three-dimensional motion analysis system (Vicon Motion System; VICON, London, UK) equipped with 18 cameras. In line with the marker placement protocol of the plug-in gait full-body model, 39 reflective markers were attached to each participant. A single marker was also placed on each pylon. Motion data were recorded at 100 Hz and processed using MATLAB (R2020b; MathWorks Inc., Natick, MA, USA). 2.3 Procedures Participants were randomly assigned to one of three groups: Task-Switching Step Exercise (TSSE), Single-Task Step Exercise (STSE), or Task-Switching Control Exercise (TSCE). The study briefing and experiment took place on the same day and lasted less than three hours. We explained the study, obtained written informed consent, and assessed participants’ gait and balance functions in relation to fall risk, along with their cognitive function. Assessments included maximum gait speed over 10 meters, the Berg Balance Scale (BBS; Berg et al. [16]), MMSE, and the Trail Making Test A and B (TMT-A, B [17]). We also measured each participant’s step length at a comfortable, self-selected walking speed to determine infrared sensor placement on the walkway. After the assessments, participants completed the main experimental session, which included a pre-test, an exercise session, and a post-test. Each pre- and post-test lasted approximately 15 minutes, and the exercise session lasted approximately 20 minutes. While all participants completed the same pre-and post-tests, the content of the exercise session—described below—varied by group. Sufficient break time was provided between the assessment session, pre-and post-tests, and exercise session to account for participant fatigue. During the pre-and post-tests, participants walked straight at a self-selected comfortable speed, then completed a 90-degree reactive turning task using a task-switching paradigm. They were instructed to pass as closely as possible to the pylon located in front of the intersection. To ensure task familiarity, participants practiced the reactive turning task before data collection. Prior to the pre-test, they performed four straight-walking trials to provide stable reference data for turning performance calculations (see Data Analysis for details). Each pre- and post-test consisted of 18 trials, six of which involved an abrupt change in direction. These trials were presented pseudo-randomly and included conditions in which the initially indicated direction either switched to the opposite direction after passing the sensor (i.e., task-switching) or remained unchanged (Figure 1-B, C). During the exercise session, all participants completed a single, individualized 20-minute exercise session. To minimize fatigue effects, they rested for approximately 10 minutes both before and after the session. The exercise protocol is summarized below (Figure 2). An illuminated arrow presented in front indicated which foot or hand should take the initial action. A total of 72 trials were conducted, with 18 trials per set. In the TSSE and TSCE groups, the illuminated arrow switched randomly to the opposite direction in one-third of the trials, coinciding with an auditory cue (i.e., task-switching paradigm). In the STSE group, the illuminated arrow remained in the initial direction when the auditory cue occurred. In the TSSE group, participants stood with feet shoulder-width apart in the starting position. They were instructed to take a step forward promptly in response to the auditory cue, then bring the back foot forward to align with the lead foot. Participants were prepared to step with the foot indicated by the illuminated arrow (e.g., right). If the arrow changed direction simultaneously with the auditory cue, they were required to switch the stepping foot quickly (e.g., to the left: task-switching condition). If the arrow did not change direction, they stepped forward with the initially indicated foot (e.g., right). The stepping direction was randomly assigned for each trial, ensuring an equal number of left and right steps. The number of trials in which the arrow changed direction was also balanced between left and right. In the STSE group, the procedure was nearly identical to that of the TSSE group. The key difference was that the direction of the illuminated arrow did not change once presented. As a result, participants executed a pre-planned step rapidly in response to the auditory cue. This group served as a control for the TSSE group, isolating the effect of task-switching by ensuring that stepping occurred without switching the stepping foot. In the TSCE group, participants were seated and instructed to push a button corresponding to the direction of the illuminated arrow (left or right) in response to the auditory cue. As in the TSSE group, the arrow direction switched according to the task-switching paradigm. Participants were informed that if the arrow switched direction, they were required to push the opposite button using the opposite hand. This group also served as a control for the TSSE group, isolating the influence of COM movement and stepping. 2.4 Data Analysis Kinematic data were obtained using the plug-in gait full-body model and low-pass filtered at 10 Hz using a fourth-order Butterworth algorithm. Four dependent measures were calculated for both pre-and post-tests: the onset time of COM shift (Onset of COM shift), the peak COM acceleration in the mediolateral direction (COM ACC peak), the root mean square of COM acceleration across three dimensions (COM ACC RMS) and the minimum margin of stability in the mediolateral direction (Min MOS). These four measures were used to test the first hypothesis. The Onset of COM shift assessed reactivity, reflecting how quickly participants shifted COM movement in response to a cue. It was defined as the point at which whole-body COM displacement in the medio-lateral direction exceeded the mean ± 3 SD of the reference straight-walking data [18]. COM ACC peak served as an indicator of COM movement control, with lower values indicating better regulation of COM acceleration. It was calculated from the moment participants passed the infrared sensor to when they completed the 90-degree turn. Higher COM ACC peak values reflect more vigorous COM movement and indicate a greater balance cost [19]. COM ACC RMS evaluated COM movement smoothness [20], with lower values representing more coordinated COM movement and smoother turning. It was calculated over the same interval as the COM ACC peak. Finally, Min MOS quantified stability during reactive turning. Higher values indicated better balance and safer turning execution. It was defined as the minimum distance between the extrapolated COM (XCOM) and the lateral malleolus marker position during the stance leg phase. XCOM was calculated according to Hof et al. [21]. The stance leg phase was defined as the phase involving the leg on the same side as the turning direction, occurring either before or after the onset of pelvic rotation [22]. Negative Min MOS values indicate that the XCOM extends beyond the lateral edge of the base of support, suggesting greater instability during turning. Statistical analyses were conducted using IBM SPSS for Windows, version 28 (IBM Corp.). To compare group characteristics, one-way analysis of variance (ANOVA) was used for age and height; Pearson’s chi-square test was used for sex; and the Kruskal-Wallis test was used for weight, maximum gait speed, BBS, MMSE, and TMT-A and B. A two-way ANOVA was performed to examine the effects of time (pre-/post-test) and group (TSSE/STSE/TSCE) on the four dependent measures. Six task-switching trials from the 18 trials in each pre- and post-test were analyzed. These trials were selected to specifically assess the impact of the exercise session on reactive turning performance under the task-switching paradigm. When the main effect of group and/or the time × group interaction was significant, post-hoc comparisons were performed using the Bonferroni method via SPSS syntax. To test the second hypothesis, Pearson correlation coefficients were used to examine associations among changes in dependent measures, exploring how improvements in one aspect of reactive turning performance were related to changes in others within each group. Changes in performance (post-test value minus pre-test value) for each measure were defined as follows. A lower Onset of COM shift indicates a quicker response during reactive turning; thus, a negative change reflects improved reactivity. A higher COM ACC peak represents more vigorous COM movement, so a negative change indicates enhanced COM movement control. Similarly, a higher COM ACC RMS suggests less fluid COM movement and a negative change reflects smoother turning. Lastly, a higher Min MOS value indicates greater stability, with a positive change reflecting the use of a safer turning strategy in the post-test. Statistical significance was set at p < 0.05. 3. Results All participants completed the protocol successfully. Table 1 presents participant characteristics. No significant group differences were found in age, height, weight, sex, gait, balance, or cognitive function ( p > 0.05). Table 1 Characteristics of the Participants TSS (N＝20) STS (N＝20) TSC (N＝20) p-value Sex (M/F) a 16/4 10/10 16/4 .06 Age (y) b 70.5 ± 3.6 69.5 ± 4.2 70.5 ± 4.4 .64 Height (cm) b 163.1 ± 6.6 162.3 ± 10.1 160.8 ± 9.4 .69 Weight (kg) c 62.6 ± 9.6 61.6 ± 14.3 59.3 ± 8.2 .42 BBS (score) c 55.9 ± 0.3 55.9 ± 0.2 55.8 ± 0.7 .80 MMSE (score) c 29.0 ± 1.5 29.3 ± 0.9 29.4 ± 0.8 .73 Max_gait_speed (m/s) c 1.9 ± 0.2 2.0 ± 0.3 1.9 ± 0.3 .43 TMT-A (sec) c 43.9 ± 16.7 40.8 ± 12.2 43.4 ± 15.3 .96 TMT-B (sec) c 97.7 ± 38.3 84.0 ± 26.4 94.8 ± 33.9 .69 Note. BBS: Berg Balance Scale (out of 56). MMSE: Mini-Mental State Examination (out of 30). TMT: Trail Making Test. a Pearson’s chi-square test. b One-way ANOVA. c Kruskal-Wallis test. Table 2 shows the two-way ANOVA results for each time point and group. A significant effect was observed only for the COM ACC peak. The main effect of time was not significant (F(1,32) = 0.11, p = 0.75, partial η2 = 0.002), nor was the main effect of group (F(2,57) = 0.44, p = 0.65, partial η2 = 0.02). However, the interaction between time and group was significant ( F (2,57) = 4.13, p = 0.021, partial η 2 = 0.13, f = 0.38). Post-hoc analysis revealed a significant difference only in the TSSE group, in which the peak COM acceleration in the post-test was lower than in the pre-test (F(1,57) = 5.34, p = 0.025, partial η2 = 0.09, f = 0.30), partially supporting the first hypothesis. No significant changes were found in the STSE group ( F (1,57) = 3.03, p = 0.09) or the TSCE group ( F (1,57) = 0.00, p = 0.99). No significant differences were observed across time or groups for Onset of COM shift, COM ACC RMS, or Min MOS. Table 2 Mean (Standard Deviation) Variables of Each Time and Groups Parameter TSSE STSE TSCE time group intersection pre post pre post pre post F-value p-value F-value p-value F-value p-value Onset of COM shift (sec) 1.09 (0.15) 1.09 (0.18) 1.11 (0.13) 1.10 (0.14) 1.16 (0.12) 1.14 (0.11) 0.38 .54 1.19 .31 0.50 .64 COM ACC peak (m/sec²) 3.35 (0.91) 3.17 (0.72) 3.01 (0.73) 3.15 (0.72) 3.09 (0.52) 3.09 (0.52) 0.11 .75 0.44 .65 4.13 .02* COM ACC RMS (m/sec²) 3.00 (0.69) 2.95 (0.72) 2.78 (0.55) 2.81 (0.55) 2.94 (0.43) 2.99 (0.46) 0.10 .76 0.63 .54 1.14 .33 Min MOS (m) -0.42 (0.12) -0.41 (0.12) -0.45 (0.13) -0.47 (0.12) -0.42 (0.14) -0.45 (0.13) 0.77 .39 0.87 .43 0.87 .42 Note . Post-hoc comparisons were conducted for COM ACC peak, which showed a significant interaction effect (group × condition) in the two-way ANOVA. The Bonferroni method revealed that peak COM acceleration significantly decreased from the post-test to the pre-test only in the TSSE group ( F (1,57) = 5.34, p = 0.025, partial η 2 = 0.09, f = 0.30). In contrast, no significant differences were observed in the STSE group ( F (1,57) = 3.03, p = 0.09) or the TSCE group ( F (1,57) = 0.00, p = 0.99). The Onset of COM shift: the onset time of COM shift. COM ACC peak: the peak COM acceleration in the mediolateral direction. COM ACC RMS: the root mean square of COM acceleration across three dimensions. Min MOS: the minimum margin of stability in the mediolateral direction. * p < .05 Table 3 presents the correlations between changes in post-test and pre-test values among the four dependent measures. A significant negative correlation was found between the change in COM ACC RMS (post-test minus pre-test) and the change in Min MOS (post-test minus pre-test) in the TSSE group only (r = –.56, p = .01; 95% CI = –0.80, –0.14). No significant correlations were observed between these measures in the STSE or TSCE groups (STSE: r = –.18, p = .44; 95% CI = –0.58, 0.29; TSCE: r = –.27, p = .25; 95% CI = –0.63, 0.21). This result indicates that participants in the TSSE group who demonstrated smoother turning in the post-test than in the pre-test, as reflected by a negative pre-post difference in the COM ACC RMS, showed a strategy associated with a lower risk of falling, as indicated by a positive pre-post difference in the Min MOS, partially supporting the second hypothesis. Significant correlations were found across all groups between the pre-post changes in COM ACC peak and COM ACC RMS, as both parameters reflected COM acceleration (TSSE: r = .70, p = .001; 95% CI = 0.36, 0.87; STSE: r = .56, p = .01; 95% CI = 0.14, 0.80; TSCE: r = .51, p = .02; 95% CI = 0.08, 0.77). No other significant correlations were found among the remaining parameters in any group. Table 3 Correlation Between the Changes in Post-test and Pre-test Among Four Dependent Measures Within Each Group TSSE STSE TSCE Onset of COM shift COM ACC peak COM ACC RMS Min MOS Onset of COM shift COM ACC peak COM ACC RMS Min MOS Onset of COM shift COM ACC peak COM ACC RMS Min MOS Onset of COM shift － Onset of COM shift － Onset of COM shift － COM ACC peak -0.084 (.72) － COM ACC peak -0.041 (.87) － COM ACC peak 0.24 (.31) － COM ACC RMS -0.43 (.06) 0.70 (.001) * － COM ACC RMS -0.097 (.68) 0.56 (.01) * － COM ACC RMS -0.085 (.72) 0.51 (.02) * － Min MOS -0.33 (.16) -0.20 (.41) -0.56 (.01) * － Min MOS -0.26 (.27) -0.029 (.90) -0.18 (.44) － Min MOS 0.23 (.34) -0.097 (.69) -0.27 (.25) － Note . The table presents correlation coefficients and p-values, formatted as r (p-value) . In the TSSE group, a significant negative correlation was found between changes in COM ACC RMS (post-test minus pre-test) and Min MOS (post-test minus pre-test). A negative change in COM ACC RMS indicated smoother turning in the post-test, while a positive change in Min MOS reflected the adoption of a safer strategy to reduce fall risk. No significant correlations were observed between these parameters in the STSE or TSCE groups. *: p < .05 4. Discussion This study aimed to address whether a novel step exercise, TSSE could improve reactive turning performance under the task-switching paradigm in healthy older adults. The first hypothesis proposed that TSSE would more effectively enhance the older participants’ ability during reactive turning compared to other exercises, and this was partially supported. Specifically, our findings suggested that TSSE helps older participants to improve their COM movement control, as reflected by a decrease in COM ACC peak from pre-test to post-test. However, the expected improvements in reactivity (Onset of COM shift), smoothness (COM ACC RMS), and safety (Min MOS) were not observed. The second hypothesis proposed that older participants who improved their performance following TSSE would exhibit safer reactive turning. This hypothesis was also partially supported. Specifically, older participants who were able to turn smoothly after TSSE adopted a safer strategy. However, other measures, such as reactivity and control of COM movement, did not show a significant association with a lower fall-risk strategy. Overall, while changes following TSSE were limited both between or within groups, our findings suggest that TSSE, despite not involving walking or turning, may contribute to refining reactive turning performance under the task-switching paradigm in healthy older adults. We considered that our first hypothesis was partially supported because TSSE and the pre- and post-tests required participants to exhibit somewhat similar control over COM movement, particularly in terms of braking COM movement during execution. Participants needed to cancel a pre-planned or an ongoing action and then plan and modify a new action under the task-switching paradigm. Adapting to the task-switching required participants to apply a brake to COM movement, allowing sufficient time to maintain balance, such as changing their stepping foot in TSSE or changing direction in reactive turning. Fujimoto and Chou [ 23 ] show that the successful execution of reactive movements necessitates the ability to control (i.e., brake) COM and report that COM acceleration during movement served as a reliable index of balance. Our results suggest that, following TSSE, participants enhanced their COM movement control during reactive turning using the task-switching paradigm. We considered our second hypothesis to be partially supported, as some participants in the TSSE group were able to execute COM movement more smoothly and more safely in the post-test. Reactive turning in older adults reduced the smoothness and stability of their COM movement [ 24 ]. Gait smoothness is a robust metric of overall body stability and is closely linked to the risk of falling [ 25 , 26 ]. Older adults who had a delayed response to sudden changes in turning direction exhibited greater pelvic rotation within a shorter period (i.e., in a less smooth manner), potentially leading to a loss of balance [ 7 ]. We believe that TSSE contributed to smoother COM movement during reactive turning, as it involved repeated practice of appropriate COM adjustments, such as canceling pre-planned steps and correcting them into opposite steps. This experience, even if the tasks themselves differed, such as stepping or turning, may have activated common response patterns for modifying actions within a task-switching paradigm. This could have enabled older participants to adjust their COM movement more smoothly during the post-test. Therefore, our results suggest that the participants in the TSSE group, who demonstrated smoother reactive turning after exercise, could adopt a safer strategy. Contrary to the first and second hypotheses, none of the groups showed significant changes regarding the Onset of COM shift, which was considered the key parameter of reactive turning performance. One possible reason for this is that the participants across all groups demonstrated high levels of physical and cognitive function (See Table 1 ). Specifically, they were capable of walking at high speeds [ 27 ], had near-full BBS scores [ 16 ], and MMSE scores [ 28 ]), and completed TMT-A and TMT-B in less time than the average for Japanese individuals [ 29 ]. These findings suggest that the older participants in this study exhibited high levels of walking capacity, low risk of falling, and high cognitive function. Consequently, it was possible for all participants to perform the COM shift quickly in both tests. This may have minimized the observable differences between the groups, leaving little room for improvement. We believe that TSSE has two important components during reactive turning under the task-switching paradigm in healthy older adults: sufficient experience in situations requiring task-switching and a safe exercise environment. First, TSSE provides individuals with substantial experience in regulating COM movement under the task-switching paradigm. Reactive turning occurs in sudden and unpredictable everyday situations, making it difficult to prepare for in advance or practice frequently. When these situations involve task-switching, even healthy older adults may struggle to prevent falls due to increased cognitive and motor demands. In a recent study, we introduced the task-switching paradigm to the reactive turning task and discovered that even healthy older adults who appear unlikely to fall were prone to imbalances, making hidden fall risks [ 7 ]. Considering that reactive turning performance under the task-switching paradigm improved after just a short 20-minute TSSE session in the present study, we believe that providing healthy older adults with sufficient experience and cognitive-motor reinforcement within this paradigm could help refine COM movement control during reactive turning and may contribute to fall prevention. Second, TSSE can be performed relatively safely, as it involves less dynamic movement than walking or turning in the task-switching paradigm. Repeatedly practicing a task prone to imbalance may instead increase the risk of a fall in older adults. We believe that ensuring a safe exercise environment is very important for older adults. Notably, the control group for STSE (quickly stepping in response to a cue) and TSCE (performing a task-switching task without COM movement) did not show performance improvement. This suggests that managing the COM movement while cancelling pre-planned or ongoing actions and adopting new ones was crucial. This study had several limitations. First, we could not quantify the participants’ performance during the exercise. Therefore, it was not possible to determine whether exercise improved functions related to performing the behavior of reactive turning. In the future, it will be necessary to verify participants’ responses during TSSE. Second, two types of sensory feedback were used as cues in the exercise (illuminated arrow and auditory cue). As the participants were preparing to step or press a button based on the direction of the illuminated arrow in the starting position, an auditory cue was required to signal the start of the action. This was particularly important for STSE and non-task-switched trials (both the TSSE and TSCE groups). Although none of the participants in this study had visual or hearing problems, using two types of sensory feedback may have affected their reactions. Third, there is a need to broaden the target population and examine the attributes of participants who may benefit from TSSE more effectively. Testing using a larger sample size or including participants at a higher risk of falls may yield additional significant findings regarding the characteristics of age-related decline. 5. Conclusion In conclusion, although the effect of TSSE was modest, the TSSE group demonstrated improved reactive turning performance under the task-switching paradigm. Notably, despite not engaging in walking or turning exercises, participants exhibited improvements in their performance during reactive turning while walking. This step exercise, grounded in task-switching paradigm, appears to enhance the key components of successful reactive turning when task-switching is required, including smoother and safer control of the COM in healthy older adults. Future studies should focus on older adults at a much higher risk of falls to further investigate the effectiveness of TSSE. Declarations Funding: This study was supported by the Saitama Prefectural University Research Grant (A 23005) and the Japan Society for the Promotion of Science KAKENHI (JP23K10406). Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the authors' organization, JSPS, or MEXT. Data Availability: The data supporting the findings of this study are available from the corresponding author upon reasonable request. This study was not preregistered. Acknowledgments: The authors thank the participants as well as the staff at the Silver Human Resources Center in Koshigaya. Author contributions: Takahito Nakamura: Conceptualization, Funding acquisition, Investigation, Methodology, Data curation, Formal analysis, Project administration, Writing – original draft. Takahiro Higuchi: Conceptualization, Methodology, Supervision, Writing – review and editing. Conflict of Interest: The authors report there are no competing interests to declare. Ethical approval : This study was approved by the Ethics Committee of Saitama Prefectural University (No. 22091). The study was conducted in accordance with the the Declaration of Helsinki. Informed consent: All participants who agreed to take part in the study received both oral and written information about its purpose and procedures. They provided written informed consent prior to participation. Participants were informed that their involvement was voluntary and that they could withdraw from the study at any time without penalty. Consent to publish anonymized data was obtained from all participants. References Thigpen MT, Light KE, Creel GL, Flynn SM. Turning difficulty characteristics of adults aged 65 years or older. Phys Ther. 2000;80:1174–87. https://doi.org/10.1093/ptj/80.12.1174 Cumming RG, Klineberg RJ. Fall frequency and characteristics and the risk of hip fractures. J Am Geriatr Soc. 1994;42:774–8. https://doi.org/10.1111/j.1532-5415.1994.tb06540.x Courtine G, Schieppati M. Human walking along a curved Path. II. Gait features and EMG patterns. Eur J Neurosci. 2003;18:191–205. https://doi.org/10.1046/j.1460-9568.2003.02737.x Imai T, Moore ST, Raphan T, Cohen B. Interaction of the body, head, and eyes during walking and turning. Exp Brain Res. 2001;136:1–18. https://doi.org/10.1007/s002210000533 Nakamura T, Higuchi T, Kikumoto T, Takeda T, Tashiro H, Hoshi F. Slower reorientation of the trunk for reactive turning while walking in hemiparesis stroke patients. J Mot Behav. 2019;51:640–6. https://doi.org/10.1080/00222895.2018.1547894 Nakamura T, Kodama K, Sakazaki J, Higuchi T. Relationship between adaptability during turning and the complexity of walking before turning in older adults. J Mot Behav. 2023;55:331–40. https://doi.org/10.1080/00222895.2023.2199692 Nakamura T, Suda Y, Higuchi T. Reactive turning behavior in older adults: age-related decrease is evident under increased task demand. Exp Aging Res. 2024:1–16. https://doi.org/10.1080/0361073X.2024.2439743 Mulligan CMS, Johnson ST, Pollard CD, Hannigan KS, Athanasiadis D, Norcross MF. Deceleration profiles between the penultimate and final steps of planned and reactive side-step cutting. J Athl Train. 2024;59:173–81. https://doi.org/10.4085/1062-6050-0007.23 Grange J, Houghton G. Task switching and cognitive control. Oxford University Press. https://doi.org/10.1093/acprof:osobl/9780199921959.001.0001; 2014 Schoene D, Lord SR, Delbaere K, Severino C, Davies TA, Smith ST. A randomized controlled pilot study of home-based step training in older people using videogame technology. PLOS One. 2013;8:e57734. https://doi.org/10.1371/journal.pone.0057734 Shigematsu R, Okura T. A novel exercise for improving lower-extremity functional fitness in the elderly. Aging Clin Exp Res. 2006;18:242–8. https://doi.org/10.1007/BF03324655 Shigematsu R, Okura T, Nakagaichi M, Tanaka K, Sakai T, Kitazumi S, et al. Square-stepping exercise and fall risk factors in older adults: a single-blind, randomized controlled trial. J Gerontol A Biol Sci Med Sci. 2008;63:76–82. https://doi.org/10.1093/gerona/63.1.76 Podsiadlo D, Richardson S. The timed “Up & Go”: a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. 1991;39:142–8. https://doi.org/10.1111/j.1532-5415.1991.tb01616.x Folstein MF, Folstein SE, McHugh PR. Mini-mental state. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12:189–98. https://doi.org/10.1016/0022-3956(75)90026-6 Faul F, Erdfelder E, Buchner A, Lang AG. Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav Res Methods. 2009;41:1149–60. https://doi.org/10.3758/BRM.41.4.1149 Berg KO, Wood-Dauphinee SL, Williams JI, Maki B. Measuring balance in the elderly: validation of an instrument. Can J Public Health. 1992;83 Suppl 2:S7–11 Rasmusson XD, Zonderman AB, Kawas C, Resnick SM. Effects of age and dementia on the Trail Making Test. Clin Neuropsychol. 1998;12:169–78. https://doi.org/10.1076/clin.12.2.169.2005 Hollands KL, van Vliet P, Zietz D, Wing A, Wright C, Hollands MA. Stroke-related differences in axial body segment coordination during preplanned and reactive changes in walking direction. Exp Brain Res. 2010;202:591–604. https://doi.org/10.1007/s00221-010-2162-1 Fujimoto M, Chou LS. Dynamic balance control during sit-to-stand movement: an examination with the center of mass acceleration. J Biomech. 2012;45:543–8. https://doi.org/10.1016/j.jbiomech.2011.11.037 Kibushi B, Maekaku K, Kimura T. Reduced center of mass acceleration during regular walking with electromyography biofeedback. Gait Posture. 2024;108:335–40. https://doi.org/10.1016/j.gaitpost.2024.01.008 Hof AL, Gazendam MG, Sinke WE. The condition for dynamic stability. J Biomech. 2005;38:1–8. https://doi.org/10.1016/j.jbiomech.2004.03.025 Tillman M, Molino J, Zaferiou AM. Frontal plane balance during preplanned and late-cued 90-degree turns while walking. J Biomech. 2022;141:111206. https://doi.org/10.1016/j.jbiomech.2022.111206 Fujimoto M, Chou LS. Sagittal plane momentum control during walking in elderly fallers. Gait Posture. 2016;45:121–6. https://doi.org/10.1016/j.gaitpost.2016.01.009 Dixon PC, Smith T, Taylor MJD, Jacobs JV, Dennerlein JT, Schiffman JM. Effect of walking surface, late-cueing, physiological characteristics of aging, and gait parameters on turn style preference in healthy, older adults. Hum Mov Sci. 2019;66:504–10. https://doi.org/10.1016/j.humov.2019.06.002 Poosri T, Boripuntakul S, Sungkarat S, Kamnardsiri T, Soontornpun A, Pinyopornpanish K. Gait smoothness during high-demand motor walking tasks in older adults with mild cognitive impairment. PLOS One. 2024;19:e0296710. https://doi.org/10.1371/journal.pone.0296710 Senden R, Savelberg HH, Grimm B, Heyligers IC, Meijer K. Accelerometry-based gait analysis, an additional objective approach to screen subjects at risk for falling. Gait Posture. 2012;36:296–300. https://doi.org/10.1016/j.gaitpost.2012.03.015 Zhang S, Otsuka R, Nishita Y, Shimokata H, Arai H. Twenty-year prospective cohort study of the association between gait speed and incident disability: the NILS-LSA project. Geriatr Gerontol Int. 2022;22:251–3. https://doi.org/10.1111/ggi.14341 Tsoi KKF, Chan JYC, Hirai HW, Wong SYS, Kwok TCY. Cognitive tests to detect dementia: a systematic review and meta-analysis. JAMA Intern Med. 2015;175:1450–8. https://doi.org/10.1001/jamainternmed.2015.2152 Hashimoto R, Meguro K, Lee E, Kasai M, Ishii H, Yamaguchi S. Effect of age and education on the Trail Making Test and determination of normative data for Japanese elderly people: the Tajiri Project. Psychiatry Clin Neurosci. 2006;60:422–8. https://doi.org/10.1111/j.1440-1819.2006.01526.x Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6333759","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":458061386,"identity":"0e9119c0-5454-4d6d-8173-9abacc13e0ba","order_by":0,"name":"Takahito Nakamura","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABG0lEQVRIiWNgGAWjYFACNjiLmYGxQYKBgb0BJnCAgBY2iBYJBh64SuK0MEgwSCTgd5Y5+7HETzfb7skzyDc/Nvi5w6KOX/L5s8c8DHbyDIxnsVpj2ZN2WDq3rdiwgY3NOLH3jISE5Owcc2MehmTDBoZzWO0zOJDeANSSwLj/GIPxAd42CQmD2zls0jwMzEDlZwywajn/vPk3UIt9Axv754N/QVpuHn8G1FKPW8uNtGMgWxIb2HiMk8G23GAwA2o5jEfLszTrnHMJyQ1sOcXGsm0SkjN7cswN5xgcN2zD5Zfzaca3c8oSbBuYj2+WfNtWx8/PfvzZgzcV1fL8EthDDCsARhXQSWwSZ4jWAYtd/h7itYyCUTAKRsFwBgD7i1o0HjAgMgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-2361-2416","institution":"Saitama Prefectural University: Saitama Kenritsu Daigaku","correspondingAuthor":true,"prefix":"","firstName":"Takahito","middleName":"","lastName":"Nakamura","suffix":""},{"id":458061387,"identity":"2638b2d6-ebde-4dc3-b67d-eb1cf4b10e6f","order_by":1,"name":"Takahiro Higuchi","email":"","orcid":"","institution":"Tokyo Metropolitan University - Minamiosawa Campus: Shuto Daigaku Tokyo","correspondingAuthor":false,"prefix":"","firstName":"Takahiro","middleName":"","lastName":"Higuchi","suffix":""}],"badges":[],"createdAt":"2025-03-29 11:17:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6333759/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6333759/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83291753,"identity":"7646b715-60b1-4621-b80e-745b891db87b","added_by":"auto","created_at":"2025-05-22 13:09:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":591420,"visible":true,"origin":"","legend":"\u003cp\u003eBird’s-eye View of the Experimental Setup (A) and the Pre-and Post-test Procedures for Reactive Turning Using the Task-switching Paradigm (B, C)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNote. A: The walkway measured 10 meters in length. An intersection measuring 0.7 m by 1.2 m was surrounded by four plastic pylons. A pair of infrared sensors were placed at a distance equivalent to each participant's two-step length before the edge of the intersection. B, C: At the start of each trial, the initial walking direction (e.g., right) was indicated (B). After passing the infrared sensors—positioned at a distance equivalent to two steps before the intersection—either the direction abruptly switched to the opposite side or remained unchanged. In trials where the direction switched (e.g., from right to left), which occurred in one-third of the total 18 trials (in both pre-and post-tests), participants were required to quickly adjust their walking direction (C).\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6333759/v1/ee3896a8ab2a662ed930fa48.png"},{"id":83290916,"identity":"fa407373-97b2-4f00-a7be-8a830b27e8d1","added_by":"auto","created_at":"2025-05-22 13:01:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":78933,"visible":true,"origin":"","legend":"\u003cp\u003eExercise Protocol for Each Group\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNote.\u003c/em\u003e \u003cem\u003eIn all exercise sessions, participants responded promptly to an auditory cue. A total of 72 trials were conducted across 20 minutes (18 trials per set). In both the TSSE and TSCE groups, the illuminated arrow randomly switched to the opposite direction in one-third of all trials. In the STSE group, the arrow direction remained unchanged. In TSSE, participants adapted their stepping foot by canceling a planned action when the task switched. They initially prepared to step with the foot indicated by the illuminated arrow (e.g., right). If the arrow changed direction with the auditory cue, they promptly switched to the opposite foot (e.g., left); otherwise, they proceeded with the originally planned foot.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6333759/v1/f775b9776debcb39a2bae8a2.png"},{"id":83291761,"identity":"fb59b437-c6b3-4887-997b-0459b73c66d2","added_by":"auto","created_at":"2025-05-22 13:10:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1237417,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6333759/v1/e235044f-7d20-40fa-9318-8efd90ca0b53.pdf"}],"financialInterests":"","formattedTitle":"Reactive Turning During Walking Improves in Healthy Older Adults with a Novel Task-switching Step Exercise","fulltext":[{"header":"Key summary points","content":"\u003cp\u003e\u003cstrong\u003eAim\u003c/strong\u003e: To investigate whether a novel task-switching step exercise (TSSE)\u0026mdash;designed to enhance reactive turning without requiring actual turning or walking\u0026mdash;could improve reactive turning performance under a task-switching paradigm in healthy older adults.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFundings\u003c/strong\u003e: Participants who completed TSSE demonstrated improved control of center of mass (COM) movement during reactive turning. Moreover, some participants in the TSSE group exhibited smoother and safer COM movement during reactive turning after exercise.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMessage\u003c/strong\u003e: TSSE has the potential to enhance reactive turning performance in healthy older adults, even without walking or turning practice.\u003c/p\u003e"},{"header":"1. Introduction","content":"\u003cp\u003eTurning while walking increases the risk of falls and related injuries in older adults [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Falls during turns are eight times more likely to result in hip fractures than those occurring during straight-walking [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. This heightened risk stems from the dynamic shift of the center of mass (COM) caused by asymmetric coordination of the inner and outer limbs [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and the spatiotemporal rotation of the body [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] in response to the external environment. Specifically, \u0026ldquo;reactive turning\u0026rdquo;\u0026mdash;a sudden turn initiated at an unpredictable moment [\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] that requires a response within a limited time\u0026mdash;poses challenges to maintaining balance in older adults.\u003c/p\u003e \u003cp\u003eThe challenges to maintaining balance during reactive turning become more pronounced when the direction of turning is suddenly changed from the pre-planned side to the opposite side, a phenomenon referred to as task-switching [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The task-switching paradigm is commonly used in psychological research [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Under this paradigm, participants of a certain task need to cancel their pre-planned or ongoing action and flexibly adapt to a new one, which induces a performance cost and contributes to reduced performance in older adults. We applied this paradigm to the reactive turning task [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], in which the direction of travel suddenly switched from the present direction (e.g., right) to the opposite direction (e.g., left) during walking. We tested healthy older adults and found that those with a delayed COM shift to the new direction exhibited larger pelvic rotations over a short period during reactive turning. This suggests that even healthy older adults had difficulty quickly responding and sufficiently rotating their bodies in the new direction when task-switching was required. Therefore, we believe that reactive turning under the task-switching paradigm has the potential to detect performance decline in healthy older adults, and it is essential to consider how to minimize the difficulties they face in this situation.\u003c/p\u003e \u003cp\u003eThe purpose of the present study was to design a new exercise incorporating the task-switching paradigm to improve reactive turning performance in healthy older adults. We consider that the ability to respond effectively to reactive turning under the task-switching paradigm is a key factor for healthy older adults in discovering potential fall risks and enhancing their performance. However, repetitive turning exercises can be burdensome for individuals facing challenges with reactive turning and may pose the risk of falling during practice. To address these concerns, a novel exercise that targets reactive turning under the task-switching paradigm with an emphasis on safety is needed. Various effective exercises, such as repeated step exercises requiring the selection of an appropriate foot contact location from multiple positions, have been reported to effectively enhance improve responsiveness and balance ability in older adults [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. In Schoene et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], a choice stepping training program required participants to step onto randomly displayed foot-ground positions. Their findings show improvements after the training in choice stepping reaction time, postural sway, dual-task ability, as assessed by a locomotor balance test, the Timed Up and Go test [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], while simultaneously performing a verbal fluency task (naming animals). Similarly, Shigematsu and Okura [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] and Shigematsu et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] have developed a square-stepping exercise program that includes forward, backward, lateral, and oblique steps with progressively more complex patterns. The findings of Shigematsu et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] reveal improvements not only in balance ability\u0026mdash;such as forward and backward tandem walking and walking around two cones\u0026mdash;but also in response time, including weight transfer time while stepping in the forward, backward, right, or left direction after a light signal (choice reaction time), in older adults following the exercise. These findings suggest that repeated-step exercises incorporating cognitive components are effective in improving responsiveness and balance management in older adults.\u003c/p\u003e \u003cp\u003eConsidering the results of these previous studies, we designed a novel step exercise focused on a task-switching paradigm, called a task-switching step exercise (TSSE). In this exercise, participants prepared to step with the foot indicated by an illuminated arrow direction (left or right) and switched feet when the arrow changed to the opposite direction alongside an auditory cue. Notably, TSSE does not involve turning and even walking. We examined whether, despite these characteristics, TSSE is beneficial to improve reactive turning performance under the task-switching paradigm.\u003c/p\u003e \u003cp\u003eIn addition to the TSSE group, we established two control exercise groups. The Single-Task Step Exercise (STSE) group served as a control for the TSSE group to assess the effect of the task-switching paradigm. Participants in this group stepped quickly in response to a cue without task-switching. The Task-Switching Control Exercise (TSCE) group served as a control for the TSSE group to isolate the effects of COM movement and stepping. Participants in this group performed task-switching without COM movement by pressing a button with their hands while seated. We first hypothesized that TSSE would enhance older adults\u0026rsquo; ability to initiate COM shift and regulate COM acceleration, resulting in improved reactivity and smoother, more stable performance during reactive turning compared to STSE and TSCE. Second, we hypothesized that older adults who initiated COM shift more quickly or demonstrated better COM acceleration control after TSSE would show greater post-test stability. To examine this, we analyzed within-group correlations between pre-and post-test changes in reactive turning performance.\u003c/p\u003e"},{"header":"2. Material and Methods","content":"\u003cp\u003e\u003cstrong\u003e2.1 Participants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSixty healthy older adults (69.9 \u0026plusmn; 4.0 years) participated in this study. All participants had normal or corrected-to-normal vision and hearing and no need for a hearing aid. Eligible participants were over 65 years of age and had a Mini-Mental State Examination (MMSE) [14] score of greater than 24. Individuals diagnosed with neurological, orthopedic, or rheumatological diseases that could interfere with locomotion were excluded. This study employed a three-group, single-blind, randomized controlled trial design. The participants were recruited through the Silver Human Resources Center in Koshigaya, Japan. The staff at the center, who were not co-authors of this study, determined the order for each participant. The sample size calculation was performed using G*Power 3.1.9.7 [15]. Assuming a two-way analysis of variance with three groups, an effect size of 0.25, a significant level of 5 %, and a power of 80 %, the required sample size was calculated to be 42 participants. This study was approved by the Ethics Committee of Saitama Prefectural University (No. 22091). All participants provided written informed consent, and the experiment adhered to the principles of the Declaration of Helsinki\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Apparatus \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe apparatus used for the reactive turning task was almost the same as that used in Nakamura et al. [7] (see Figure 1). The walkway measured 10 meters in length and five meters in width. At a point 6.3 meters from the starting line, an intersection measuring 70 cm by 120 cm was marked by four plastic pylons, each 90 cm in height. A visual cue system comprising a direction indicator (Applied Office, Edogawa, Japan) with illuminated arrows was installed at eye level at the walkway\u0026rsquo;s end. The direction arrows were illuminated before participants began walking. A pair of infrared sensors were placed at a distance corresponding to two-step lengths from each participant before the edge of the intersection. The same direction indicator system was used during the exercise session. Participants either stood or sat at the intersection edge, approximately four meters from the visual cue. For the TSCE group, two buttons (50 mm \u0026times; 50 mm), one for each hand, were used, and the cue was adjusted to sitting eye level. Whole-body kinematics were recorded using a three-dimensional motion analysis system (Vicon Motion System; VICON, London, UK) equipped with 18 cameras. In line with the marker placement protocol of the plug-in gait full-body model, 39 reflective markers were attached to each participant. A single marker was also placed on each pylon. Motion data were recorded at 100 Hz and processed using MATLAB (R2020b; MathWorks Inc., Natick, MA, USA).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Procedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eParticipants were randomly assigned to one of three groups: Task-Switching Step Exercise (TSSE), Single-Task Step Exercise (STSE), or Task-Switching Control Exercise (TSCE). The study briefing and experiment took place on the same day and lasted less than three hours. We explained the study, obtained written informed consent, and assessed participants\u0026rsquo; gait and balance functions in relation to fall risk, along with their cognitive function. Assessments included maximum gait speed over 10 meters, the Berg Balance Scale (BBS; Berg et al. [16]), MMSE, and the Trail Making Test A and B (TMT-A, B [17]). We also measured each participant\u0026rsquo;s step length at a comfortable, self-selected walking speed to determine infrared sensor placement on the walkway. After the assessments, participants completed the main experimental session, which included a pre-test, an exercise session, and a post-test. Each pre- and post-test lasted approximately 15 minutes, and the exercise session lasted approximately 20 minutes. While all participants completed the same pre-and post-tests, the content of the exercise session\u0026mdash;described below\u0026mdash;varied by group. Sufficient break time was provided between the assessment session, pre-and post-tests, and exercise session to account for participant fatigue.\u003c/p\u003e\n\u003cp\u003eDuring the pre-and post-tests, participants walked straight at a self-selected comfortable speed, then completed a 90-degree reactive turning task using a task-switching paradigm. They were instructed to pass as closely as possible to the pylon located in front of the intersection. To ensure task familiarity, participants practiced the reactive turning task before data collection. Prior to the pre-test, they performed four straight-walking trials to provide stable reference data for turning performance calculations (see Data Analysis for details). Each pre- and post-test consisted of 18 trials, six of which involved an abrupt change in direction. These trials were presented pseudo-randomly and included conditions in which the initially indicated direction either switched to the opposite direction after passing the sensor (i.e., task-switching) or remained unchanged (Figure 1-B, C).\u003c/p\u003e\n\u003cp\u003eDuring the exercise session, all participants completed a single, individualized 20-minute exercise session. To minimize fatigue effects, they rested for approximately 10 minutes both before and after the session. The exercise protocol is summarized below (Figure 2). An illuminated arrow presented in front indicated which foot or hand should take the initial action. A total of 72 trials were conducted, with 18 trials per set. In the TSSE and TSCE groups, the illuminated arrow switched randomly to the opposite direction in one-third of the trials, coinciding with an auditory cue (i.e., task-switching paradigm). In the STSE group, the illuminated arrow remained in the initial direction when the auditory cue occurred. \u003c/p\u003e\n\u003cp\u003eIn the TSSE group, participants stood with feet shoulder-width apart in the starting position. They were instructed to take a step forward promptly in response to the auditory cue, then bring the back foot forward to align with the lead foot. Participants were prepared to step with the foot indicated by the illuminated arrow (e.g., right). If the arrow changed direction simultaneously with the auditory cue, they were required to switch the stepping foot quickly (e.g., to the left: task-switching condition). If the arrow did not change direction, they stepped forward with the initially indicated foot (e.g., right). The stepping direction was randomly assigned for each trial, ensuring an equal number of left and right steps. The number of trials in which the arrow changed direction was also balanced between left and right.\u003c/p\u003e\n\u003cp\u003eIn the STSE group, the procedure was nearly identical to that of the TSSE group. The key difference was that the direction of the illuminated arrow did not change once presented. As a result, participants executed a pre-planned step rapidly in response to the auditory cue. This group served as a control for the TSSE group, isolating the effect of task-switching by ensuring that stepping occurred without switching the stepping foot. In the TSCE group, participants were seated and instructed to push a button corresponding to the direction of the illuminated arrow (left or right) in response to the auditory cue. As in the TSSE group, the arrow direction switched according to the task-switching paradigm. Participants were informed that if the arrow switched direction, they were required to push the opposite button using the opposite hand. This group also served as a control for the TSSE group, isolating the influence of COM movement and stepping. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Data Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKinematic data were obtained using the plug-in gait full-body model and low-pass filtered at 10 Hz using a fourth-order Butterworth algorithm. Four dependent measures were calculated for both pre-and post-tests: the onset time of COM shift (Onset of COM shift), the peak COM acceleration in the mediolateral direction (COM ACC peak), the root mean square of COM acceleration across three dimensions (COM ACC RMS) and the minimum margin of stability in the mediolateral direction (Min MOS). These four measures were used to test the first hypothesis. The Onset of COM shift assessed reactivity, reflecting how quickly participants shifted COM movement in response to a cue. It was defined as the point at which whole-body COM displacement in the medio-lateral direction exceeded the mean \u0026plusmn; 3 SD of the reference straight-walking data [18]. COM ACC peak served as an indicator of COM movement control, with lower values indicating better regulation of COM acceleration. It was calculated from the moment participants passed the infrared sensor to when they completed the 90-degree turn. Higher COM ACC peak values reflect more vigorous COM movement and indicate a greater balance cost [19]. COM ACC RMS evaluated COM movement smoothness [20], with lower values representing more coordinated COM movement and smoother turning. It was calculated over the same interval as the COM ACC peak. Finally, Min MOS quantified stability during reactive turning. Higher values indicated better balance and safer turning execution. It was defined as the minimum distance between the extrapolated COM (XCOM) and the lateral malleolus marker position during the stance leg phase. XCOM was calculated according to Hof et al. [21]. The stance leg phase was defined as the phase involving the leg on the same side as the turning direction, occurring either before or after the onset of pelvic rotation [22]. Negative Min MOS values indicate that the XCOM extends beyond the lateral edge of the base of support, suggesting greater instability during turning.\u003c/p\u003e\n\u003cp\u003eStatistical analyses were conducted using IBM SPSS for Windows, version 28 (IBM Corp.). To compare group characteristics, one-way analysis of variance (ANOVA) was used for age and height; Pearson\u0026rsquo;s chi-square test was used for sex; and the Kruskal-Wallis test was used for weight, maximum gait speed, BBS, MMSE, and TMT-A and B. A two-way ANOVA was performed to examine the effects of time (pre-/post-test) and group (TSSE/STSE/TSCE) on the four dependent measures. Six task-switching trials from the 18 trials in each pre- and post-test were analyzed. These trials were selected to specifically assess the impact of the exercise session on reactive turning performance under the task-switching paradigm. When the main effect of group and/or the time \u0026times; group interaction was significant, post-hoc comparisons were performed using the Bonferroni method via SPSS syntax. To test the second hypothesis, Pearson correlation coefficients were used to examine associations among changes in dependent measures, exploring how improvements in one aspect of reactive turning performance were related to changes in others within each group. Changes in performance (post-test value minus pre-test value) for each measure were defined as follows. A lower Onset of COM shift indicates a quicker response during reactive turning; thus, a negative change reflects improved reactivity. A higher COM ACC peak represents more vigorous COM movement, so a negative change indicates enhanced COM movement control. Similarly, a higher COM ACC RMS suggests less fluid COM movement and a negative change reflects smoother turning. Lastly, a higher Min MOS value indicates greater stability, with a positive change reflecting the use of a safer turning strategy in the post-test. Statistical significance was set at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003eAll participants completed the protocol successfully. Table 1 presents participant characteristics. No significant group differences were found in age, height, weight, sex, gait, balance, or cognitive function (\u003cem\u003ep\u003c/em\u003e \u0026gt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e \u003cem\u003eCharacteristics of the Participants\u003c/em\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"558\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 168px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eTSS (N＝20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003eSTS (N＝20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003eTSC (N＝20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eSex (M/F) \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e16/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003e10/10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003e16/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.06\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eAge (y) \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e70.5 \u0026plusmn; 3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e69.5 \u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e70.5 \u0026plusmn; 4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eHeight (cm) \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e163.1 \u0026plusmn; 6.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e162.3 \u0026plusmn; 10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e160.8 \u0026plusmn; 9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eWeight (kg) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e62.6 \u0026plusmn; 9.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e61.6 \u0026plusmn; 14.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e59.3 \u0026plusmn; 8.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eBBS (score) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e55.9 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e55.9 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e55.8 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMMSE (score) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e29.0 \u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e29.3 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e29.4 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.73\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMax_gait_speed (m/s) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e1.9 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003e2.0 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 110px;\"\u003e\n \u003cp\u003e1.9 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eTMT-A (sec) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e43.9 \u0026plusmn; 16.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e40.8 \u0026plusmn; 12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e43.4 \u0026plusmn; 15.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eTMT-B (sec) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 103px;\"\u003e\n \u003cp\u003e97.7 \u0026plusmn; 38.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e84.0 \u0026plusmn; 26.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 110px;\"\u003e\n \u003cp\u003e94.8 \u0026plusmn; 33.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 66px;\"\u003e\n \u003cp\u003e.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNote.\u003c/em\u003e BBS: Berg Balance Scale (out of 56). MMSE: Mini-Mental State Examination (out of 30). TMT: Trail Making Test.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003e Pearson\u0026rsquo;s chi-square test.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003e One-way ANOVA.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003e Kruskal-Wallis test.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2 shows the two-way ANOVA results for each time point and group. A significant effect was observed only for the COM ACC peak. The main effect of time was not significant (F(1,32) = 0.11, p = 0.75, partial \u0026eta;2 = 0.002), nor was the main effect of group (F(2,57) = 0.44, p = 0.65, partial \u0026eta;2 = 0.02). However, the interaction between time and group was significant (\u003cem\u003eF\u003c/em\u003e (2,57) = 4.13, \u003cem\u003ep\u003c/em\u003e = 0.021, partial \u003cem\u003e\u0026eta;\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e = 0.13, \u003cem\u003ef\u003c/em\u003e = 0.38). Post-hoc analysis revealed a significant difference only in the TSSE group, in which the peak COM acceleration in the post-test was lower than in the pre-test (F(1,57) = 5.34, p = 0.025, partial \u0026eta;2 = 0.09, f = 0.30), partially supporting the first hypothesis. No significant changes were found in the STSE group (\u003cem\u003eF\u003c/em\u003e (1,57) = 3.03, \u003cem\u003ep\u003c/em\u003e = 0.09) or the TSCE group (\u003cem\u003eF\u003c/em\u003e (1,57) = 0.00, \u003cem\u003ep\u003c/em\u003e = 0.99). No significant differences were observed across time or groups for Onset of COM shift, COM ACC RMS, or Min MOS.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e\u003cem\u003eMean (Standard Deviation) Variables of Each Time and Groups Parameter\u003c/em\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"924\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 120px;\"\u003e\n \u003cp\u003eTSSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 111px;\"\u003e\n \u003cp\u003eSTSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 111px;\"\u003e\n \u003cp\u003eTSCE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 129px;\"\u003e\n \u003cp\u003etime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 132px;\"\u003e\n \u003cp\u003egroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 132px;\"\u003e\n \u003cp\u003eintersection\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eF-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eF-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eF-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003eOnset of COM shift (sec)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e1.09\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e1.09\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003e1.11\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e1.10\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e1.16\u003c/p\u003e\n \u003cp\u003e(0.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e1.14\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e1.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003eCOM ACC peak (m/sec\u0026sup2;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e3.35\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.91)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e3.17\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003e3.01\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.73)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e3.15\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e3.09\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e3.09\u003c/p\u003e\n \u003cp\u003e(0.52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e4.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;.02*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003eCOM ACC RMS (m/sec\u0026sup2;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e3.00\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.69)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e2.95\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003e2.78\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.55)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e2.81\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.55)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e2.94\u003c/p\u003e\n \u003cp\u003e(0.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e2.99\u003c/p\u003e\n \u003cp\u003e(0.46)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e1.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.33\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003cp\u003e(m)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e-0.42\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.41\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003e-0.45\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e-0.47\u003c/p\u003e\n \u003cp\u003e(0.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 57px;\"\u003e\n \u003cp\u003e-0.42\u003c/p\u003e\n \u003cp\u003e(0.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e-0.45\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(0.13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e0.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eNote\u003cem\u003e.\u003c/em\u003e Post-hoc comparisons were conducted for COM ACC peak, which showed a significant interaction effect (group \u0026times; condition) in the two-way ANOVA. The Bonferroni method revealed that peak COM acceleration significantly decreased from the post-test to the pre-test only in the TSSE group (\u003cem\u003eF\u003c/em\u003e (1,57) = 5.34, \u003cem\u003ep\u003c/em\u003e = 0.025, partial \u003cem\u003e\u0026eta;\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e = 0.09, \u003cem\u003ef\u003c/em\u003e = 0.30). In contrast, no significant differences were observed in the STSE group (\u003cem\u003eF\u003c/em\u003e (1,57) = 3.03, \u003cem\u003ep\u003c/em\u003e = 0.09) or the TSCE group (\u003cem\u003eF\u003c/em\u003e (1,57) = 0.00, \u003cem\u003ep\u003c/em\u003e = 0.99). The Onset of COM shift: the onset time of COM shift. COM ACC peak: the peak COM acceleration in the mediolateral direction. COM ACC RMS: the root mean square of COM acceleration across three dimensions. Min MOS: the minimum margin of stability in the mediolateral direction.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e* \u003cem\u003ep\u003c/em\u003e \u0026lt; .05 \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 3 presents the correlations between changes in post-test and pre-test values among the four dependent measures. A significant negative correlation was found between the change in COM ACC RMS (post-test minus pre-test) and the change in Min MOS (post-test minus pre-test) in the TSSE group only (r = \u0026ndash;.56, p = .01; 95% CI = \u0026ndash;0.80, \u0026ndash;0.14). No significant correlations were observed between these measures in the STSE or TSCE groups (STSE: r = \u0026ndash;.18, p = .44; 95% CI = \u0026ndash;0.58, 0.29; TSCE: r = \u0026ndash;.27, p = .25; 95% CI = \u0026ndash;0.63, 0.21). This result indicates that participants in the TSSE group who demonstrated smoother turning in the post-test than in the pre-test, as reflected by a negative pre-post difference in the COM ACC RMS, showed a strategy associated with a lower risk of falling, as indicated by a positive pre-post difference in the Min MOS, partially supporting the second hypothesis. Significant correlations were found across all groups between the pre-post changes in COM ACC peak and COM ACC RMS, as both parameters reflected COM acceleration (TSSE: r = .70, p = .001; 95% CI = 0.36, 0.87; STSE: r = .56, p = .01; 95% CI = 0.14, 0.80; TSCE: r = .51, p = .02; 95% CI = 0.08, 0.77). No other significant correlations were found among the remaining parameters in any group.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u0026nbsp;\u003c/strong\u003e\u003cem\u003eCorrelation Between the Changes in Post-test and Pre-test Among Four Dependent Measures Within Each Group\u003c/em\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"932\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" style=\"width: 300px;\"\u003e\n \u003cp\u003eTSSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" style=\"width: 300px;\"\u003e\n \u003cp\u003eSTSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" style=\"width: 300px;\"\u003e\n \u003cp\u003eTSCE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56px;\"\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003eOnset of COM shift\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e-0.084\u003c/p\u003e\n \u003cp\u003e(.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e-0.041\u003c/p\u003e\n \u003cp\u003e(.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC peak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003cp\u003e(.31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e-0.43\u003c/p\u003e\n \u003cp\u003e(.06)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e0.70\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(.001) *\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e-0.097\u003c/p\u003e\n \u003cp\u003e(.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;(.01) *\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCOM ACC RMS\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e-0.085\u003c/p\u003e\n \u003cp\u003e(.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.51\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003cstrong\u003e(.02) *\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.33\u003c/p\u003e\n \u003cp\u003e(.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.20\u003c/p\u003e\n \u003cp\u003e(.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.56\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;(.01) *\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.26\u003c/p\u003e\n \u003cp\u003e(.27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.029\u003c/p\u003e\n \u003cp\u003e(.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.18\u003c/p\u003e\n \u003cp\u003e(.44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 16px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eMin MOS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e0.23\u003c/p\u003e\n \u003cp\u003e(.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.097\u003c/p\u003e\n \u003cp\u003e(.69)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e-0.27\u003c/p\u003e\n \u003cp\u003e(.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e－\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eNote\u003cem\u003e.\u003c/em\u003e The table presents correlation coefficients and p-values, formatted as \u003cem\u003er (p-value)\u003c/em\u003e. In the TSSE group, a significant negative correlation was found between changes in COM ACC RMS (post-test minus pre-test) and Min MOS (post-test minus pre-test). A negative change in COM ACC RMS indicated smoother turning in the post-test, while a positive change in Min MOS reflected the adoption of a safer strategy to reduce fall risk. No significant correlations were observed between these parameters in the STSE or TSCE groups. *: \u003cem\u003ep\u003c/em\u003e \u0026lt; .05\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study aimed to address whether a novel step exercise, TSSE could improve reactive turning performance under the task-switching paradigm in healthy older adults. The first hypothesis proposed that TSSE would more effectively enhance the older participants\u0026rsquo; ability during reactive turning compared to other exercises, and this was partially supported. Specifically, our findings suggested that TSSE helps older participants to improve their COM movement control, as reflected by a decrease in COM ACC peak from pre-test to post-test. However, the expected improvements in reactivity (Onset of COM shift), smoothness (COM ACC RMS), and safety (Min MOS) were not observed. The second hypothesis proposed that older participants who improved their performance following TSSE would exhibit safer reactive turning. This hypothesis was also partially supported. Specifically, older participants who were able to turn smoothly after TSSE adopted a safer strategy. However, other measures, such as reactivity and control of COM movement, did not show a significant association with a lower fall-risk strategy. Overall, while changes following TSSE were limited both between or within groups, our findings suggest that TSSE, despite not involving walking or turning, may contribute to refining reactive turning performance under the task-switching paradigm in healthy older adults.\u003c/p\u003e \u003cp\u003eWe considered that our first hypothesis was partially supported because TSSE and the pre- and post-tests required participants to exhibit somewhat similar control over COM movement, particularly in terms of braking COM movement during execution. Participants needed to cancel a pre-planned or an ongoing action and then plan and modify a new action under the task-switching paradigm. Adapting to the task-switching required participants to apply a brake to COM movement, allowing sufficient time to maintain balance, such as changing their stepping foot in TSSE or changing direction in reactive turning. Fujimoto and Chou [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] show that the successful execution of reactive movements necessitates the ability to control (i.e., brake) COM and report that COM acceleration during movement served as a reliable index of balance. Our results suggest that, following TSSE, participants enhanced their COM movement control during reactive turning using the task-switching paradigm.\u003c/p\u003e \u003cp\u003eWe considered our second hypothesis to be partially supported, as some participants in the TSSE group were able to execute COM movement more smoothly and more safely in the post-test. Reactive turning in older adults reduced the smoothness and stability of their COM movement [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Gait smoothness is a robust metric of overall body stability and is closely linked to the risk of falling [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Older adults who had a delayed response to sudden changes in turning direction exhibited greater pelvic rotation within a shorter period (i.e., in a less smooth manner), potentially leading to a loss of balance [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. We believe that TSSE contributed to smoother COM movement during reactive turning, as it involved repeated practice of appropriate COM adjustments, such as canceling pre-planned steps and correcting them into opposite steps. This experience, even if the tasks themselves differed, such as stepping or turning, may have activated common response patterns for modifying actions within a task-switching paradigm. This could have enabled older participants to adjust their COM movement more smoothly during the post-test. Therefore, our results suggest that the participants in the TSSE group, who demonstrated smoother reactive turning after exercise, could adopt a safer strategy.\u003c/p\u003e \u003cp\u003eContrary to the first and second hypotheses, none of the groups showed significant changes regarding the Onset of COM shift, which was considered the key parameter of reactive turning performance. One possible reason for this is that the participants across all groups demonstrated high levels of physical and cognitive function (See Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Specifically, they were capable of walking at high speeds [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], had near-full BBS scores [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], and MMSE scores [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]), and completed TMT-A and TMT-B in less time than the average for Japanese individuals [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. These findings suggest that the older participants in this study exhibited high levels of walking capacity, low risk of falling, and high cognitive function. Consequently, it was possible for all participants to perform the COM shift quickly in both tests. This may have minimized the observable differences between the groups, leaving little room for improvement.\u003c/p\u003e \u003cp\u003eWe believe that TSSE has two important components during reactive turning under the task-switching paradigm in healthy older adults: sufficient experience in situations requiring task-switching and a safe exercise environment. First, TSSE provides individuals with substantial experience in regulating COM movement under the task-switching paradigm. Reactive turning occurs in sudden and unpredictable everyday situations, making it difficult to prepare for in advance or practice frequently. When these situations involve task-switching, even healthy older adults may struggle to prevent falls due to increased cognitive and motor demands. In a recent study, we introduced the task-switching paradigm to the reactive turning task and discovered that even healthy older adults who appear unlikely to fall were prone to imbalances, making hidden fall risks [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Considering that reactive turning performance under the task-switching paradigm improved after just a short 20-minute TSSE session in the present study, we believe that providing healthy older adults with sufficient experience and cognitive-motor reinforcement within this paradigm could help refine COM movement control during reactive turning and may contribute to fall prevention. Second, TSSE can be performed relatively safely, as it involves less dynamic movement than walking or turning in the task-switching paradigm. Repeatedly practicing a task prone to imbalance may instead increase the risk of a fall in older adults. We believe that ensuring a safe exercise environment is very important for older adults. Notably, the control group for STSE (quickly stepping in response to a cue) and TSCE (performing a task-switching task without COM movement) did not show performance improvement. This suggests that managing the COM movement while cancelling pre-planned or ongoing actions and adopting new ones was crucial. This study had several limitations. First, we could not quantify the participants\u0026rsquo; performance during the exercise. Therefore, it was not possible to determine whether exercise improved functions related to performing the behavior of reactive turning. In the future, it will be necessary to verify participants\u0026rsquo; responses during TSSE. Second, two types of sensory feedback were used as cues in the exercise (illuminated arrow and auditory cue). As the participants were preparing to step or press a button based on the direction of the illuminated arrow in the starting position, an auditory cue was required to signal the start of the action. This was particularly important for STSE and non-task-switched trials (both the TSSE and TSCE groups). Although none of the participants in this study had visual or hearing problems, using two types of sensory feedback may have affected their reactions. Third, there is a need to broaden the target population and examine the attributes of participants who may benefit from TSSE more effectively. Testing using a larger sample size or including participants at a higher risk of falls may yield additional significant findings regarding the characteristics of age-related decline.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn conclusion, although the effect of TSSE was modest, the TSSE group demonstrated improved reactive turning performance under the task-switching paradigm. Notably, despite not engaging in walking or turning exercises, participants exhibited improvements in their performance during reactive turning while walking. This step exercise, grounded in task-switching paradigm, appears to enhance the key components of successful reactive turning when task-switching is required, including smoother and safer control of the COM in healthy older adults. Future studies should focus on older adults at a much higher risk of falls to further investigate the effectiveness of TSSE.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This study was supported by the Saitama Prefectural University Research Grant (A 23005) and the Japan Society for the Promotion of Science KAKENHI (JP23K10406). Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the authors\u0026apos; organization, JSPS, or MEXT.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u003c/strong\u003e The data supporting the findings of this study are available from the corresponding author upon reasonable request. This study was not preregistered.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e The authors thank the participants as well as the staff at the Silver Human Resources Center in Koshigaya.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e Takahito Nakamura: Conceptualization, Funding acquisition, Investigation, Methodology, Data curation, Formal analysis, Project administration, Writing \u0026ndash; original draft. Takahiro Higuchi: Conceptualization, Methodology, Supervision, Writing \u0026ndash; review and editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e The authors report there are no competing interests to declare.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval\u003c/strong\u003e\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003eThis study was approved by the Ethics Committee of Saitama Prefectural University (No. 22091). The study was conducted in accordance with the the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent:\u003c/strong\u003e All participants who agreed to take part in the study received both oral and written information about its purpose and procedures. They provided written informed consent prior to participation. Participants were informed that their involvement was voluntary and that they could withdraw from the study at any time without penalty. Consent to publish anonymized data was obtained from all participants.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eThigpen MT, Light KE, Creel GL, Flynn SM. Turning difficulty characteristics of adults aged 65 years or older. Phys Ther. 2000;80:1174\u0026ndash;87. https://doi.org/10.1093/ptj/80.12.1174\u003c/li\u003e\n\u003cli\u003eCumming RG, Klineberg RJ. Fall frequency and characteristics and the risk of hip fractures. J Am Geriatr Soc. 1994;42:774\u0026ndash;8. https://doi.org/10.1111/j.1532-5415.1994.tb06540.x\u003c/li\u003e\n\u003cli\u003eCourtine G, Schieppati M. Human walking along a curved Path. II. Gait features and EMG patterns. Eur J Neurosci. 2003;18:191\u0026ndash;205. https://doi.org/10.1046/j.1460-9568.2003.02737.x\u003c/li\u003e\n\u003cli\u003eImai T, Moore ST, Raphan T, Cohen B. Interaction of the body, head, and eyes during walking and turning. Exp Brain Res. 2001;136:1\u0026ndash;18. https://doi.org/10.1007/s002210000533\u003c/li\u003e\n\u003cli\u003eNakamura T, Higuchi T, Kikumoto T, Takeda T, Tashiro H, Hoshi F. Slower reorientation of the trunk for reactive turning while walking in hemiparesis stroke patients. J Mot Behav. 2019;51:640\u0026ndash;6. https://doi.org/10.1080/00222895.2018.1547894\u003c/li\u003e\n\u003cli\u003eNakamura T, Kodama K, Sakazaki J, Higuchi T. Relationship between adaptability during turning and the complexity of walking before turning in older adults. J Mot Behav. 2023;55:331\u0026ndash;40. https://doi.org/10.1080/00222895.2023.2199692\u003c/li\u003e\n\u003cli\u003eNakamura T, Suda Y, Higuchi T. Reactive turning behavior in older adults: age-related decrease is evident under increased task demand. Exp Aging Res. 2024:1\u0026ndash;16. https://doi.org/10.1080/0361073X.2024.2439743\u003c/li\u003e\n\u003cli\u003eMulligan CMS, Johnson ST, Pollard CD, Hannigan KS, Athanasiadis D, Norcross MF. Deceleration profiles between the penultimate and final steps of planned and reactive side-step cutting. J Athl Train. 2024;59:173\u0026ndash;81. https://doi.org/10.4085/1062-6050-0007.23\u003c/li\u003e\n\u003cli\u003eGrange J, Houghton G. Task switching and cognitive control. Oxford University Press. https://doi.org/10.1093/acprof:osobl/9780199921959.001.0001; 2014\u003c/li\u003e\n\u003cli\u003eSchoene D, Lord SR, Delbaere K, Severino C, Davies TA, Smith ST. A randomized controlled pilot study of home-based step training in older people using videogame technology. PLOS One. 2013;8:e57734. https://doi.org/10.1371/journal.pone.0057734\u003c/li\u003e\n\u003cli\u003eShigematsu R, Okura T. A novel exercise for improving lower-extremity functional fitness in the elderly. Aging Clin Exp Res. 2006;18:242\u0026ndash;8. https://doi.org/10.1007/BF03324655\u003c/li\u003e\n\u003cli\u003eShigematsu R, Okura T, Nakagaichi M, Tanaka K, Sakai T, Kitazumi S, et al. Square-stepping exercise and fall risk factors in older adults: a single-blind, randomized controlled trial. J Gerontol A Biol Sci Med Sci. 2008;63:76\u0026ndash;82. https://doi.org/10.1093/gerona/63.1.76\u003c/li\u003e\n\u003cli\u003ePodsiadlo D, Richardson S. The timed \u0026ldquo;Up \u0026amp; Go\u0026rdquo;: a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. 1991;39:142\u0026ndash;8. https://doi.org/10.1111/j.1532-5415.1991.tb01616.x\u003c/li\u003e\n\u003cli\u003eFolstein MF, Folstein SE, McHugh PR. Mini-mental state. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12:189\u0026ndash;98. https://doi.org/10.1016/0022-3956(75)90026-6\u003c/li\u003e\n\u003cli\u003eFaul F, Erdfelder E, Buchner A, Lang AG. Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav Res Methods. 2009;41:1149\u0026ndash;60. https://doi.org/10.3758/BRM.41.4.1149\u003c/li\u003e\n\u003cli\u003eBerg KO, Wood-Dauphinee SL, Williams JI, Maki B. Measuring balance in the elderly: validation of an instrument. Can J Public Health. 1992;83 Suppl 2:S7\u0026ndash;11\u003c/li\u003e\n\u003cli\u003eRasmusson XD, Zonderman AB, Kawas C, Resnick SM. Effects of age and dementia on the Trail Making Test. Clin Neuropsychol. 1998;12:169\u0026ndash;78. https://doi.org/10.1076/clin.12.2.169.2005\u003c/li\u003e\n\u003cli\u003eHollands KL, van Vliet P, Zietz D, Wing A, Wright C, Hollands MA. Stroke-related differences in axial body segment coordination during preplanned and reactive changes in walking direction. Exp Brain Res. 2010;202:591\u0026ndash;604. https://doi.org/10.1007/s00221-010-2162-1\u003c/li\u003e\n\u003cli\u003eFujimoto M, Chou LS. Dynamic balance control during sit-to-stand movement: an examination with the center of mass acceleration. J Biomech. 2012;45:543\u0026ndash;8. https://doi.org/10.1016/j.jbiomech.2011.11.037\u003c/li\u003e\n\u003cli\u003eKibushi B, Maekaku K, Kimura T. Reduced center of mass acceleration during regular walking with electromyography biofeedback. Gait Posture. 2024;108:335\u0026ndash;40. https://doi.org/10.1016/j.gaitpost.2024.01.008\u003c/li\u003e\n\u003cli\u003eHof AL, Gazendam MG, Sinke WE. The condition for dynamic stability. J Biomech. 2005;38:1\u0026ndash;8. https://doi.org/10.1016/j.jbiomech.2004.03.025\u003c/li\u003e\n\u003cli\u003eTillman M, Molino J, Zaferiou AM. Frontal plane balance during preplanned and late-cued 90-degree turns while walking. J Biomech. 2022;141:111206. https://doi.org/10.1016/j.jbiomech.2022.111206\u003c/li\u003e\n\u003cli\u003eFujimoto M, Chou LS. Sagittal plane momentum control during walking in elderly fallers. Gait Posture. 2016;45:121\u0026ndash;6. https://doi.org/10.1016/j.gaitpost.2016.01.009\u003c/li\u003e\n\u003cli\u003eDixon PC, Smith T, Taylor MJD, Jacobs JV, Dennerlein JT, Schiffman JM. Effect of walking surface, late-cueing, physiological characteristics of aging, and gait parameters on turn style preference in healthy, older adults. Hum Mov Sci. 2019;66:504\u0026ndash;10. https://doi.org/10.1016/j.humov.2019.06.002\u003c/li\u003e\n\u003cli\u003ePoosri T, Boripuntakul S, Sungkarat S, Kamnardsiri T, Soontornpun A, Pinyopornpanish K. Gait smoothness during high-demand motor walking tasks in older adults with mild cognitive impairment. PLOS One. 2024;19:e0296710. https://doi.org/10.1371/journal.pone.0296710\u003c/li\u003e\n\u003cli\u003eSenden R, Savelberg HH, Grimm B, Heyligers IC, Meijer K. Accelerometry-based gait analysis, an additional objective approach to screen subjects at risk for falling. Gait Posture. 2012;36:296\u0026ndash;300. https://doi.org/10.1016/j.gaitpost.2012.03.015\u003c/li\u003e\n\u003cli\u003eZhang S, Otsuka R, Nishita Y, Shimokata H, Arai H. Twenty-year prospective cohort study of the association between gait speed and incident disability: the NILS-LSA project. Geriatr Gerontol Int. 2022;22:251\u0026ndash;3. https://doi.org/10.1111/ggi.14341\u003c/li\u003e\n\u003cli\u003eTsoi KKF, Chan JYC, Hirai HW, Wong SYS, Kwok TCY. Cognitive tests to detect dementia: a systematic review and meta-analysis. JAMA Intern Med. 2015;175:1450\u0026ndash;8. https://doi.org/10.1001/jamainternmed.2015.2152\u003c/li\u003e\n\u003cli\u003eHashimoto R, Meguro K, Lee E, Kasai M, Ishii H, Yamaguchi S. Effect of age and education on the Trail Making Test and determination of normative data for Japanese elderly people: the Tajiri Project. Psychiatry Clin Neurosci. 2006;60:422\u0026ndash;8. https://doi.org/10.1111/j.1440-1819.2006.01526.x\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"reactive turning, task-switching paradigm, center of mass, step, exercise","lastPublishedDoi":"10.21203/rs.3.rs-6333759/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6333759/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e: Older adults often experience difficulty maintaining balance during reactive turning while walking, which can occur suddenly and unpredictably. These challenges become more pronounced when the turning direction suddenly switches from the pre-planned side to the opposite side, a phenomenon known as task-switching. This study examined whether Task-Switching Step Exercise (TSSE) designed to enhance reactive turning without requiring turning and even walking—could improve reactive turning performance under a task-switching paradigm in healthy older adults.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: Sixty healthy older adults (69.9 ± 4.0 years) were randomly assigned to three groups. The TSSE group prepared a step with the foot indicated by an illuminated arrow and switched feet when the arrow direction changed alongside an auditory cue. The Single-Task Step Exercise group performed pre-planned steps as quickly as possible without task-switching. The Task-Switching Control Exercise group pushed a button while seated, following the task-switching paradigm. All participants completed a single 20-minute exercise session. Pre- and post-tests involved 90-degree reactive turning while walking under the task-switching paradigm.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: The TSSE group demonstrated significant improvement in center of mass (COM) control, with a reduction in COM acceleration peak from pre- to post-test (p = 0.025). Correlation analyses suggested that some TSSE participants executed COM movement more smoothly and safely during the post-test (\u003cem\u003er\u003c/em\u003e = -0.56, \u003cem\u003ep\u003c/em\u003e = 0.01).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: Although the effect of TSSE was modest, the exercise may still contribute to improved reactive turning performance in healthy older adults by supporting COM control, even without walking or turning practice.\u003c/p\u003e","manuscriptTitle":"Reactive Turning During Walking Improves in Healthy Older Adults with a Novel Task-switching Step Exercise","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-22 13:01:51","doi":"10.21203/rs.3.rs-6333759/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"70ebccea-701f-4d13-9914-382f4e9340a7","owner":[],"postedDate":"May 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-22T13:01:51+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-22 13:01:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6333759","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6333759","identity":"rs-6333759","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}